An image capturing device, equipped with a correction means capable of correcting a captured image (an image of a subject such as a white board, a book, etc. captured by the device) as if the subject were shot from the front even when the subject is shot from a direction oblique to the front of the subject, is well known today. Such a correction means makes the correction by detecting the three-dimensional shape of the subject based on the captured image of the subject. A portable digital camera equipped with such a correction means has been disclosed in, for example, FIG. 1, etc. of Japanese Patent Provisional Publication No.HEI09-289611 (hereinafter referred to as a “document No. 1”).
As an example of a technique for detecting the three-dimensional shape of the subject as parameters necessary for the aforementioned correction means, a three-dimensional shape measurement device of a stationary type, extracting slit beams (as an example of pattern light) projected on the subject by subtracting a slit-beamless image (obtained by shooting the subject on which no slit beams are projected) from a slit-beamed image (obtained by shooting the subject on which the slit beams are projected) and detecting the three-dimensional shape of the subject based on the extracted slit beams, has been disclosed in the tenth paragraph, FIG. 3, etc. of Japanese Patent Publication No.3282331 (hereinafter referred to as a “document No.2”).